ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-4-7403-2004

Column ozone and aerosol optical properties retrieved from direct solar irradiance measurements during SOLVE II

Swartz

W. H.

¹ Yee

J.-H.

¹ Shetter

R. E.

² Hall

S. R.

² Lefer

B. L.

² ⁶ Livingston

J. M.

³ Russell

P. B.

⁴ Browell

E. V.

⁵ Avery

M. A.

⁵

The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA

National Center for Atmospheric Research, Boulder, Colorado, USA

SRI International, Menlo Park, California, USA

NASA Ames Research Center, Moffett Field, California, USA

NASA Langley Research Center, Hampton, Virginia, USA

now at: University of Houston, Department of Geosciences, Houston, Texas, USA

09 11 2004

4 6 7403 7431

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Direct observation of the Sun at large solar zenith angles during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II)/Validation of International Satellites and study of Ozone Loss (VINTERSOL) campaign by several instruments provided a rich dataset for the retrieval and analysis of line-of-sight column composition, intercomparison, and measurement validation. A flexible, multi-species spectral fitting technique is presented and applied to spectral solar irradiance measurements made by the NCAR Direct beam Irradiance Atmospheric Spectrometer (DIAS) on-board the NASA DC-8. The approach allows for the independent retrieval of O3, O2·O2, and aerosol optical properties, by constraining Rayleigh extinction. We examine the 19 January 2003 and 6 February 2003 flights and find very good agreement of O3 and O2·O2 retrievals with forward-modeling calculations, even at large solar zenith angles, where refraction is important. Intercomparisons of retrieved ozone and aerosol optical thickness with results from the Ames Airborne Tracking Sunphotometer (AATS-14) are summarized.